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Updated: Feb 6, 2026
A Freeze-Thawing Method to Prepare Chitosan-Polyvinyl alcohol Hydrogels Without Crosslinking Agents and Diflunisal Release Studies
Published on: January 14, 2020
Methylene blue removal from water using the hydrogel beads of poly(vinyl alcohol)-sodium
Wei Wang1, Yunliang Zhao2, Haoyu Bai1
1School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China.
Abstract:
Poly(vinyl alcohol)-sodium alginate-chitosan-montmorillonite nanosheets (MMTNS) hydrogel beads with porous and steady structure were fabricated via hydrogen-bond and electrostatic interactions, and were characterized by FTIR, TG, SEM and effecting tests. The results suggested MMTNS could support and maintain the porous structure, making an open excess for MB molecules. The increasing proportion of MMTNS in hydrogel beads enhanced the MB removal. Hydrogel beads possessed higher affinity to MB at high pHs due to the stronger electronegativity triggered by deprotonation of hydroxyls. Moreover, hydrogel beads had a good stability and reusability. The adsorption process was correlated with Elovich kinetics model, and fitted well with Freundlich, Redlich-Peterson and Sips isotherm models. The adsorption of MB on hydrogel beads was a disorderliness, endothermic and spontaneous process detected by the thrmodynamic. MB molecules reacted with the oxygen atoms in hydroxyl and substitute the Na+ in MMTNS were proved by EDS, XPS and Na+ concentration variation.
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